Drop alerta-web and prometheus_gainsight image defaults from docker swarm

Alerta-web and prometheus_gainsight image defaults already set in defaults
docker_images class.

Change-Id: I0d361162470611748465f55c4e1ea7dc54ee84dc
diff --git a/docker/swarm/stack/monitoring/alerta.yml b/docker/swarm/stack/monitoring/alerta.yml
index 0f82821..6112b60 100644
--- a/docker/swarm/stack/monitoring/alerta.yml
+++ b/docker/swarm/stack/monitoring/alerta.yml
@@ -2,7 +2,6 @@
 - system.prometheus.alerta
 parameters:
   _param:
-    docker_image_alerta: ${_param:mcp_docker_registry}/mirantis/external/alerta-web:latest
     alerta_mongodb_uri: "mongodb://${_param:cluster_node01_address}:27017,${_param:cluster_node02_address}:27017,${_param:cluster_node03_address}:27017/alerta?replicaSet=stacklight"
     alerta_admin_username: "admin@alerta.io"
   docker:
diff --git a/docker/swarm/stack/monitoring/gainsight.yml b/docker/swarm/stack/monitoring/gainsight.yml
index 06c87aa..755fbf8 100644
--- a/docker/swarm/stack/monitoring/gainsight.yml
+++ b/docker/swarm/stack/monitoring/gainsight.yml
@@ -14,7 +14,6 @@
     gainsight_config_directory: '/srv/gainsight'
     gainsight_crontab_directory: '/etc/cron.d'
     gainsight_config_path: "${_param:gainsight_config_directory}/config.ini"
-    docker_image_prometheus_gainsight: '${_param:mcp_docker_registry}/openstack-docker/gainsight:nightly'
   docker:
     client:
       stack: